2.8 setting up different viewport shading options for different viewport windows?
Thanks guys, so looks like what I'm after is...

1) Setup 4 viewports (don't use Quad View), 

2) Make all of them Ortho viewports except the top right viewport (ie make it Perspective)

3) Then in the perspective viewport  select the blueprint Empty object and in Object Data turn off Display Perspective

Giving me wireframes against the blueprints, but a solid view of the tank in a perspective view without the distraction of the blueprints, ie...



Thanks again.